The $1.5 million masterpiece by Helen Frankenthaler that was damaged last week when a 12-year-old boy stuck a wad of chewing gum on the canvas was removed from display at the Detroit Institute of Arts on Thursday and taken to the museum's conservation lab for repairs.

Museum officials said they are optimistic that the picture will make a full recovery. But in contrast to comments earlier this week in which relieved officials said decisively that the 1963 painting, "The Bay," would be fine, the museum issued a more tempered statement Thursday.

"The DIA has moved 'The Bay' to its conservation laboratory for study and treatment," Becky Hart, assistant curator of contemporary art, read from the statement. "As research into treatment is still at an early stage, we cannot accurately predict how long it will take or its final outcome. However, we remain optimistic that the painting can be fully restored and are devoting our energies to that end."

On Feb. 24, the student visited the museum with a group from the Holly Academy, a charter school in Oakland County, and stuck a piece of half-chewed Wrigley's Extra Polar Ice to the lower left-hand corner of Frankenthaler's abstract painting, a prize of the DIA's collection and a landmark in the artist's career. The gum left a quarter-size stain on the canvas.

The student, whose name has not been released, has been suspended. The director of the Holly Academy said the boy's parents punished him, though details were not available.

No conservators at the museum were available for comment Thursday, but Peter VanDyke, communications coordinator at the DIA, said they had been discussing the case with colleagues from around the country in Internet chat rooms. The conservators have also learned what chemicals are in the gum, a key to choosing the proper solvent for cleaning.

"The conservators are still working feverishly to do research and treat the residue," VanDyke said.